For your first question, that sounds absolutely fine. All that matters is that the ship itself has no fics. Characters that are mentioned or even hypothetical/implied are 100% okay. (I'm even allowing OCs for this round!) Your second ship also definitely still qualifies. Threesomes/poly/etc. are separate ships altogether, and even if they weren't, fics where the ship is not the main relationship do not count against it.

Thanks for the questions, and I'm happy to hear you have multiple ships you're interested in writing. :)